Telephonic repeating circuit and apparatus.



PATENTED' MAR. 19, 1907.

F. E. DE P. D' HUMY. TBLEPHONIG REPBATING CIRCUIT AND APPARATUS.

APPLICATION IILBD JUNE 26. 1906.

2 SHEETS-SHEET 1.

No 847,777. PATENTED MAR. 19, 1907. P. E. DE F. DHU'MY. TELEPHONIGRBPEATING CIRCUIT AND APPARATUS..

APPLICATION FILED JUNE 26, 1906.

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. I 2 SHEETS-SHEET 2.

' transmission in either direction at the will of articulation from thereceiver. Attempts TED s'rA'rEs PATENT OFFICE.

Specification of Letters Patent.

TELEPHONIC .REPEATING CIRCUIT AND APPARATUS- Patented March 19, 1907.

Application filed June 26,1906. Serial No. 323,482.

To all whont it may concern:

Be it-known that I, FERNAND EMILE DE FAUCHEUX DiIUMY, a citizen of theUnited States, residing at Englewood, in the county of Bergen and Stateof New Jersey, have invented certain new and useful Improvements inTelephonic Repeating Circuits and Apparatus, of which the following is aspecification, reference being had to the drawings accompanying andforming part of the same.

One of the most 'serious'difiiculties met with in telephonictransmission over lon circuits is the unavoidable attenuation o thecurrent, due to well-known causes, thereby rendering the action on thedistant receiving instruments correspondingly weak. To remedy thisdrawback, it'has been proposed to divide the circuit in'to comparativelyshort sections and to repeat or reproduce the current-waves in onesection after another from the transmitting end of the system to thereceiving end witha fresh source of current and correspondin 1yamplified waves in each section. It is oi course desirablein fact, it ispractically essentialthat such a system be reciprocal-that is, operativefor.

the arties usin the line and not in one direction only. umerous systemsbased on this plan have been roposed but so far as I am aware none of tese numerous attempts has been productive of practical results. The useof relays with two line-circuits, as commonly employed, is productiveonly of a sustained hum or shriek in the instrument, due to the factthat waves relayed from one line into the other are relayed back intothe first, then again into the second, and back into the first, and arethus tossed back and forth at the rate of the vibrating'attunement ofthe relays. Furthermore, any reciprocal repeater which sends waves backinto the originating or sending circuit causes distortion of theoriginal wavesto a greater or less degree,for the reason that the relayarmature or diaphragm possesses a certain inertia whichcauses' it to lagsl i htly behind the waves which actuate it. onsequently any waves whichthe relay sends into the originating-circuit will be slightly in arrearof the original waves, producing resultant distorted waves, which arecarriedto the second linecircuit and reach the receiving end thereof intheir distorted form, thereby'seriously impairing the distinctness orclearness of the which are in series with their appropriateline-circuits the other differential windings are put in series withartificial-line loads having resistance, capacity, and inductance equalto the transmission-circuit.v Hence although the system referred to isactually reciprocal in operation it fails to produce the results forwhich a repeating system is intended, for the addition of the artificiallines, through which the new currents must flow, brings each circuit, ineffect, up to the orignal total length of the line efore it was di.

vided.

I have therefore been led to devise my present invention, which has forits chief object to provide, first, a reciprocal repeating system inwhich the direction of transmission is changed at the will of theparties using the line by the mere act of speaking into the transmitterwithout the use of automatic switches; second, a system in whichamplified current-waves are sentinto the second or receiving linecircuit, but not in the first or originating line circuit also; third, asystem in which reciprocal operation may be obtained with or withoutdifferentially-wound relays, but without attenuating the-current by anartificial line in series with the receiving-line.

The nature of the invention by which these objects are attained will bemore readily understood from a description of the preferred embodiments,which are illustratedin the annexed drawings, wherein Figure 1 is adiagram showing the preferred form. Figs. 2 and 3 are diagrams showingmodifications.

Referring now to Fig. 1, R and R. indicate two microphone relays of anysuitable type, with the usual local circuits L L, but havingtheirreceiving magnets wound differentially, as indicated at 1' r and r 1*",respec- .IIO

tively. C C are the east and west tel ephonecircuits, respectively, inwhich are the windings t t of transformers T T. The other windings t tof these transformers are in ductance, and capacity equalto itsrespective line-circuit C or C. a

The operation of the system will now be readily understood. If avoice-current be produced in thetelephone-circuit C, correspondingcurrent will be induced in the transformer T, in the winding t thereof,flowing through the differential winding 1' of the relay R, and thencedividing to the ground through windings i and t of transformers T and Trespectively. The diaphragm of the relay is thereby actuated in eorres0ndence with the current-waves in the tele onecircuit and causes fresh,stronger, an inde-' pendent but exactly similar'current-waves to be setup in the winding t of transformer T These current-waves flow to therelaymagnet R, where the current divides and flowsin opposite orneutralizing directions on account of the equal loads on the twobranches of the magnet-Winding. Part of the currentthus divided flows totransformer T and artificial line A and thence to ground, while theother part flows to groundthrough the winding t (which now becomes aprimary) of the transformer T. The fresh strong current in the primary tinduces similar'current-with corresponding waves in the other winding t,(now the secondary,) which current-waves are propagated to the telephonein circuit G At the same time no effect is produced on the relay localcircuit Lcand telephone-circuit C, since therelay R" is not affected.Consequently the voice wave's originating'in line C are reproduced inline C, inductively through transformer T,electromechanlcally andinductively through relay R, and inductively through transformer T, andthat without affecting in any way the original waves in circuit C.Conversely, by an exactly similar operation voice-waves I in circuit Care reproduced in circuit C.

Fig; 2 shows a slightly-different arrangement in regard to thedifferential relays. In this case the relay-transformers are eachprovided with two secondaries t and t", which are connected to theappropriate differential windings of the other relay instead ofa's'i'ngle secondary connected at the neutral point of the other relaymagnet winding.

ays being secured by means of-the trans-- formers T T, whose windings. tt are connected at their middle points with the windings fitrespectively, of transformers T T.

In this case current induced in transformerwinding t, for example flowsto the middle point of transformer-winding t, where it divides, halfflowin to ground through the transformer T an the other half flowing toground by way of the artificial line A. The current induced in the otherwinding of transformer T actuates the relay R The current therebyinduced in the latters transformer-winding t flows to the middle pointof the winding 25 of the transformer T and dividing there flows equallythrough the two halves, one of which includes the transformer T, andcauses the current to be induced or repeated in line-circuit C, whilethe other half includes (inductively) the balancing-Circuit orartificial line A. The currents in the two halves of winding 6, however,ai'e. in .opposite directions, and hence neutralizeeach other so far asany effect on the other winding of the transformer is conoerned. Conseuently the relay R although not di erentially wound, is neverthelessunaffected, and likewise the originating-circuit C. In the same waycurrents originating in line-circuit C will he reproduced in the otherwithout affecting the relay R From the foregoing descri 7tl01'1 it willbe seen that the s stein in loot forms is fully reciprocal wit out theuse of automatic switches, the direction of transmission being changedat will b the 'act of speaking into the transmitter o thereceiving-station, and that the amplified current-waves are producedonly in the receiving-circuit C or C, as the case may be, and not in theoriginating circuit. There can therefore be no deforming of the originalwaves, with consequent impairment of clearness at the receiving end ofthe system, nor can current-waves be thrown back and forth between thetwo circuits, with the objectionable humming or singing. It will also beseen that the currents produced in the transformers T T divide at thedifferential devices. which, as explained above, may be either rela s ortransformers, half of the current in uencing inductively thetransmission line-circuit through transformer T or T, as the case maybe, and the other half inductively influencing the respective artificialline, thereby bringing the two influencing-circuits into multiplerelation with each other. The consequent attenuation of the current insuch an arrangement is only that due-to the natural loss'orstraightening effect in the transmission-circuits, which loss is muchless than would result in a series relation.

It is to be understood, of course, that the arrangements hereindescribed are merely typical of the invention, which may be emtem, incombination, a telephone-line consisting of independent sections,repeating devices having differential windings, portions of theirwindings being in inductive relation to respective sections of thetelephone-line, and artificial-line loads in inductive relation to otherportions of the windings of the repeating devices, as set forth.

3. In a telephonic repeating .system, in combination, atelephone-lineconsisting of independent sections, a device having differentialwindings, one ofthe differential windings being connected inductivelywith one of the line-sections, means for producing in the saiddifferential device currents correspond ing to currents in the otherline-section, and an artificial-line load connected inductively withanother winding of the differential device, as set forth.

4. In a telephone repeating system, in combination, a telephone-lineconsisting of independent sections, a device having differentialwindings, one of the differential windings being connected inductivelywith one of the line-sections, an artificial-line load connectedinductively with another winding of the differential device, and acircuit in inductive relation to the other line-section and connected tothe neutral point of the winding of the differential device, assetforth.

5. In a telephonic repeating system, in combination, a telephone-lineconsisting of independentsections, a relay having a differentially-woundreceiving-magnet, one of the differential windings being connectedinduct-' ively with one of the line-sections, an artificial lin.e loadconnected inductivel with the other differential winding of the re ayreceiving-magnet, and a circuit in inductive relation to the otherline-section and adapted to produce currents in the relay correspondingto currents in the said line-section as setforth.

.6. In a telephonic repeating system, in combination, a telephone-lineconsisting of independent sections, a relay having adifferentially-wound receivinganagnet, one of the differential windingsbeing connected inductively with one of the line-section's,anartificial-line'load connected inductively with the other differentialwinding of the relay receiving-m agnet, and a circuit in inductiverelation to the other line-section and connected to the neutral point ofthe windings of the relay receiving-magnet, as set forth.

7. In a telephonic repeating system, in

combination, a telephone-line consisting of independent sections, arelay having a differentially-wound receiving-111agnet, one of thedifferential windings being connected inductively with the one of thelinesections, means for producing in the said differential devicecurrents corresponding to currents in the other line-section, and anartificial-line load connected inductively with another differentialwinding of the relay receiving-magnet, as set forth.

8. In a reciprocal telephonic repeating system, in combination, atelephone-line con sisting of independent sections, repeating-relayshaving differentially-wound receivingmagnets, portions of thedifferential windings' being in inductive relation torespective sectionsof the telephone-line, and artificialline loads in inductive relation toother portions of the differential windings of the relayreceiving-magnets, as set forth.

'9. In a reciprocal telephonic repeating system, a dividedtelephone-hne, repeating-relays having differentially-woundreceivingmagnets, and artificial-line loads, the said artificial-lineloads and the sections of the responsive to currents originated in itsrespective line-section and. unresponsive to currents produced by it inthe other line-section,- as set forth.

12'. In a telephonic repeating system, a relayhaving adifferentially-wound receiving magnet inductively connected with'atransmission-line and an artificial line, as set forth.

FERNAND EMILE DE FAUCHEUX IYHUMY.

Witnesses:

STURGES S. DUNHAM, THOS. J. BYRNES.

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